Specific Latent Heat

• SLH – the amount of energy needed to change 1kg of a substance from one state to another without changing its temperature  

   
• So while SHC of a substance is involved with absorbing thermal energy to increase the temperature of the substance, SLH of a substance is involved with absorbing the thermal energy to overcome forces and change state while its temperature is staying constant. 
• There are two types of SLH, Fusion and vaporisation. 

   
• The SLH for changing between a solid and a liquid (melting or freezing) is called specific latent heat of fusion. 

   
• The SLH for changing between a liquid and a gas is called specific latent heat of vaporisation.  
• E= m L  

  E= energy for a state change (J) 

  m= mass (kg) 

  L=Specific Latent Heat (J/kg)